CLINICAL CORE - CORE B: ABSTRACT The Clinical Core (Core B) plays a pivotal role in the BIOCARD Study. The Clinical Core is responsible for: (1) the re-enrollment of BIOCARD subjects, (2) scheduling subjects for all visits and all study procedures (including clinical/cognitive assessments, lumbar punctures for collection of cerebrospinal fluid, magnetic resonance imaging (MRI) scans, and positron emission tomography scans using Pittsburgh compound B (PiB/PET scans), (3) completion of annual clinical and cognitive assessments, (4) acquisition of ante-mortem autopsy approval, (5) implementation of subject retention activities, (6) analyses of clinical and cognitive data concerning the study participants, (7) working collaboratively with the other Cores to examine combinations of biomarkers that are predictive of progression and to examine the order and pattern of biomarker change during preclinical AD, and (8) sharing of clinical and cognitive data with investigators in the field via the BIOCARD website, using the approved BIOCARD Study data sharing procedures.